This invention relates to a system and method for depositing a pattern of media and in particular, to a system and method for depositing granules in a frame pattern.
A common method of manufacturing roofing materials involves depositing granules on a coated sheet of material, such as a web material that is coated with asphalt. A common roofing material is the roofing shingle which presents a well defined and pleasing pattern on a roof. Shingles are time consuming to install, however, and the seams present a potential source of water leaks. Although a continuous sheet of roofing material would be preferable, such a continuous sheet lacks the distinctive xe2x80x9cshinglexe2x80x9d pattern users have grown accustomed to.
Some attempts have been made at depositing granule patterns on a continuous sheet of material. The continuous sheet of material is unrolled, coated with a tacky material such as asphalt, and moved beneath a granule application device that drops granules onto the tacky coating covering the sheet. Existing granule application devices are limited in that they are not capable of depositing granules in a well defined pattern, such as a pattern formed by groups of different colored granules, referred to as xe2x80x9cblend drops.xe2x80x9d Such patterns can be used to simulate traditional slate or wood roofs and would save considerable time in the roofing industry.
A typical granule application device uses a hopper and a roll rotating beneath the hopper to allow the granules to fall onto the moving sheet of roofing material itself. However, such devices do not adequately control the falling of the granules onto the moving sheet of roofing material and do not allow the granules to be deposited precisely in a well defined pattern. In particular, the edges of the xe2x80x9cblend dropsxe2x80x9d can not be squared or made the same length.
Accordingly, what is needed is a system and method for precisely depositing granule xe2x80x9cblend dropsxe2x80x9d in a pattern, for example, simulating traditional slate or wood roofs.
The present invention features a method of depositing a plurality of color groups of granules to form a predefined pattern. The method comprises moving a sheet of material having an adhesive material on a surface thereof. A first group of granules is deposited on the moving sheet of material. The first group of granules has a first color and forms a first predefined blend drop pattern defining an inner region. A second group of granules is then deposited on the moving sheet within the inner region of the first predefined pattern of the first group of granules. The second group of granules has a second color and forms, a second predefined blend drop pattern. The first predefined blend drop pattern and the second predefined blend drop pattern define an intermediate region therebetween. A third group of granules is then deposited on the moving sheet. The third group of granules adheres to the moving sheet at least in the intermediate region between the first and second group of granules, thereby forming the predefined pattern.
According to the preferred method, the first predefined blend pattern is a frame pattern, and the second predefined blend drop pattern is a solid pattern. The step of depositing the third group of granules preferably includes depositing a curtain of granules over the moving web. The third group of granules can be the same as the first color or a different third color.
The present invention also features a system for depositing granules in the predefined pattern. The system includes a mechanism for moving a web and a coater for coating the web with an asphalt composition. The system also includes first and second media applicators for depositing the respective first and second groups of granules in the respective first and second predefined blend drop patterns. The first and second media applicators preferably include a hopper containing the respective granules, a media applicator roll for receiving the granules and depositing the granules on the web in the respective predefined blend drop pattern, and a media retaining member for maintaining the granules in the respective predefined blend drop pattern on the media applicator roll. The system also includes a third media, applicator for depositing a third group of granules over the first and second groups of granules.